Efficiency of gall-inducing insects in the biological control of parthenium weed : Structural, metabolic and physiological changes
- Authors: Florentine, Singarayer , Raman, Anantanarayanan , Dhileepan, Kunjithapatham
- Date: 2001
- Type: Text , Journal article
- Relation: Antenna Vol. 25, no. (2001), p. 47-52
- Full Text: false
- Description: 2003004181
Gall-inducing insects and biological control of Parthenium hysterophorus L. (Asteraceae)
- Authors: Florentine, Singarayer , Raman, Anantanarayanan , Dhileepan, Kunjithapatham
- Date: 2001
- Type: Text , Journal article
- Relation: Plant Protection Quarterly Vol. 16, no. 2 (2001), p. 63-68
- Full Text:
- Reviewed:
- Description: 2003004178
Heat requirement for germination of the grass, panicum laevinode
- Authors: Florentine, Singarayer , Graham, R.A. , Fox, John
- Date: 2002
- Type: Text , Journal article
- Relation: International Journal of Ecology and Environmental Sciences Vol. 28, no. (2002), p. 143-145
- Full Text: false
- Reviewed:
- Description: Annual grasses are important components of vegetation, especially where perennial grasses have declined from overgrazing. Panicum laevinode is an annual grass that occurs in large numbers in grassy Eucalyptus victrix L. Johnson and K. Hill coolibah woodland in Pilbara, Western Australia. Little is known about the seed germination pattern and requirements of this grass. Our aim was to examine the effect of heat pre-treatment on seed germination of P. laevinode. Only 12% germination was observed from seeds pre-treated at 60oC for periods ranging from 1 to 8 weeks. However seed viability study showed that 61.5% and 71.5% of seeds were viable from 3 and 17 months respectively. Germination study did not reflect results of the viability test.
- Description: 2003000151
Morphological and physiological adaptations to waterlogging by Eucalyptus seedlings from the semi-arid Pilbara, Western Australia
- Authors: Florentine, Singarayer , Fox, John
- Date: 2002
- Type: Text , Journal article
- Relation: The Journal of the Royal Society of Western Australia Vol. 85, no. (2002), p. 61-70
- Full Text:
- Reviewed:
- Description: This study was undertaken to investigate the adaptation to long term waterlogging of semi-arid eucalyptus species. Long-term waterlogging of Eucalyptus victrix seedlings significantly increases seedling stem diameter. Flooding reduces photosynthesis, transpiration and stomatal conductance. Flooding does not increase shoot fresh or dry weight of 4-, 8- or 17- week old seedlings. Leaf emergence may be stimulated for flooded seedlings compared with unflooded seedlings. Root dry weight is not significantly greater for 17- week old flooded plants than 13- week old seedlings. We suggest that maintenance of a high root/shoot ratio is a drought adaptation. Furthermore, a comparative study of flood tolerance in semi-arid eucalypt species suggests that those species intolerant of flooding seldom express morphological adaptations and fail to recover from physiological damage. Flooding significantly reduced the transpiration rate and stomatal conduct of all three species. Diurnal transpiration, stomatal conductance and leaf water potential of E. terminalis and E. leucophloia were significantly different between treatment (flooding) and control seedlings.
- Description: C1
- Description: 2003000132
Responses of the weed parthenium hysterophorus (Asteraceae) to the stem Gall-inducing Weevil Conotrachelus albocinereus (Coleoptera: Curculionidae)
- Authors: Florentine, Singarayer , Westbrooke, Martin , Dhileepan, Kunjithapatham
- Date: 2002
- Type: Text , Journal article
- Relation: Entomologia Generalis Vol. 26, no. 3 (2002), p. 195-206
- Full Text:
- Reviewed:
- Description: A slem-galling weevil COT/o/rad,e/us alboeinereus Fiedler 1940 from Argentina is being field released to regulate populations of the weed Parlhenium hysterophorus in Queensland, Australia since 1995. In this paper we report the tissue and metabolic responses in P hyslerophorus in the context of the biology and feeding behaviour of the weevil. C albocinereus induces elliptical galls often on the main shoot axes and rarely on the terminal and axillary mcristems of the host plant. From oviposition through gall maturation, the structure and metabolism of the host-plant tissues. especially at the gall region, change continuously to accommodate pressure inflicted by the feeding larva. The host plant shows re-dirtttion of its vital metabolites to the gall, and to the lTlCtaplasitd cells of nutrition in particular. In mature galls. the pith parenchyma elements tum lignified. Larval feeding fractures the vertical continuity of vascular tissues, which affects the host plant's overall metabolism As the larva tunnels the shoot eolulTVl. it places the frass at the fissured vascular sites. That activity initialcs n«rosis and eventual death of the living eells of the vascular tissue complex. Such a development induces water.logging stress in the gall and the evapotranspirauonal system displays contrasting responses. Pennanenl1y closed Siomatal apertures and abnonnally inflated substomatal chambers indicate that P hYSleropltorus suffers moisture-stress with cecidogenesis. The larval performance triggers moisture inundation in the galled shoot and this appears to be an advantage in using this weevil in the control of P hyslerop/rorus.
- Description: C1
- Description: 2003004175
Allelopathic effects of Eucalyptus victrix L. on Eucalyptus species and grasses
- Authors: Florentine, Singarayer , Fox, John
- Date: 2003
- Type: Text , Journal article
- Relation: Allelopathy Journal Vol. 11, no. 1 (2003), p. 77-83
- Full Text: false
- Reviewed:
- Description: C1
- Description: 2003000583
Allelopathic potential of the newly emerging weed solanum mauritianum Scop. (solanaceae) in the wet tropics of north-east Queensland
- Authors: Florentine, Singarayer , Westbrooke, Martin
- Date: 2003
- Type: Text , Journal article
- Relation: Plant Protection Quarterly Vol. 18, no. 1 (2003), p. 23-25
- Full Text:
- Reviewed:
- Description: Solanum mauritianum
- Description: C1
- Description: 2003004172
Competition between Eucalyptus victrix seedlings and grass species
- Authors: Florentine, Singarayer , Fox, John
- Date: 2003
- Type: Text , Journal article
- Relation: Ecological Research Vol. 18, no. 1 (Jan 2003), p. 25-39
- Full Text: false
- Reviewed:
- Description: Competition in a natural system may be interspecific or intraspecific. In semiarid ecosystems, competition for resources between established neighboring grass species and newly recruited seedlings is very high. To examine the effects of grass species density, growing space and time of establishment on Eucalyptus victrix seedlings (interspecific competition), and the effect of density and growing space within E. victrix (intraspecific competition) we conducted an experiment under controlled conditions. We tested four hypotheses (i) E. victrix seedling growth is not affected by grass density; (ii) there is no difference in E. victrix survival and growth between early and later grass establishment; (iii) interspecific competition is not more intense than intraspecific competition in E. victrix ; and (iv) growth of E. victrix seedlings is not dependent on available growing space. In a monoculture of E. victrix , seedling mortality was higher (10%) in large pots. In mixed culture pots, where E. victrix seedlings and grass seedlings were planted on the same day, E. victrix seedlings survived for up to 4 weeks, but started to die after week five in the smallest pots. However, mortalities occurred in pots of all sizes when grass was established before E. victrix seedlings. Results also indicated that the resources necessary for the growth of individual E. victrix seedlings were more limiting under conditions of increased density of neighboring grass species rather than intraspecific competition. In particular, photosynthetic area of E. victrix seedlings was drastically reduced in mixed cultures. Although density, pot size and time of planting had impacts on E. victrix seedlings, the patterns of these impacts were variable.
- Description: C1
- Description: 2003000544
Effects of windthrow on a Eucalyptus delegatensis (Myrtaceae) stand and early understorey succession at Snowy River National Park, Victoria
- Authors: Florentine, Singarayer , Westbrooke, Martin
- Date: 2003
- Type: Text , Report
- Full Text:
- Reviewed:
- Description: The June 1998 a severe windstorm at Snowy River National Park near Mt. Gelantipy caused severe damage to a stand of Eucalyptus delegatensis. Little is known about the impact of windthrow on E. delegatensis and subsequent seedling recruitment. This study was undertaken 4.5 years later to examine (i) the windthrow damage on E. delegatensis and the understorey Acacia dealbata (type of damage, diameter class distribution), (ii) the influence of tree size (diameter at breast height, 1.3m) on pattern of tree damage (snapped/uprooted/ snapped and resprouting) (iii) undergrowth in the windthrow area compared with control plots, (iv) species composition of soil stored seed bank in windthrow damaged plots and control plots. Eleven (25 x 25 m2) plots within damaged areas and five plots within undamaged (control) were selected for study. Tree diameter at 1.3 from the rooting point and type of damage (snapped, uprooted, snapped resprouted, snapped dead) were recorded. To examine seedling recruitment, each 25 x 25 m2 plot was further divided into 1 x 1 m2 sub-plots. Within each sub plot, all E. delegatensis seedlings and their diameters were recorded. Soil seed bank species composition was examined by taking 88 and 40 soil samples from windthrow and control sites respectively. Soil samples were placed in punnets and new recruits were counted and identified. This study showed that, high winds toppled virtually all trees regardless of size and species damaging 99% of E. delegatensis. Seedling recruitment was 49 ha-1 for the canopy species E. delegatensis and 2,210 ha-1 for the sub-canopy species A. dealbata. No E. delegatensis or A. dealbata seedlings were recorded in the control plots. In the soil seed bank study five species were recovered from soil samples collected from the control and six from the windthrow damaged sites. The canopy species E. delegatensis recruited only from the windthrow site. The exotic Rubus fruticosus was found to be colonizing the windthrow site, but was not present in the control site. Results show that E. delegatensis recruitment is very poor in the damaged area and species colonizing within the windthrow damaged area were light-demanding or early succession species. It is proposed that seedling recruitment in the winthrow sites be promoted by burning the site and broadcasting E. delegatensis seed.
- Description: K1
- Description: 2003000710
Flowering, fruiting, germination and seed despersal of the newly emerging weed Solanum mauritianum Scop. (solanaceae) in the wet tropics of north Queensland
- Authors: Florentine, Singarayer , Westbrooke, Martin , Craig, M.
- Date: 2003
- Type: Text , Journal article
- Relation: Plant Protection Quarterly Vol. 18, no. 3 (2003), p. 116-120
- Full Text:
- Reviewed:
- Description: Solanum mauritianum (wild tobacco) has recently become a weed of major concern in some agricultural production areas, and tropical rainforest restoration sites, of the Atherton Tablelands, north Queensland. Until recently, little was known about the ecology of this species. A study was conducted to examine: Ii) the flowering, fruiting pattern, (ii) seed germination pattern, (iii) density of soil stored seed bank, and (iv) potential avian seed dispersers of S. mauritianum. Flowering and fruiting patterns were studied on-randomly selected plants within the study site over a period of 35 days. A germination study was performed on green (unripe) and yellow (ripe) fruits with seeds from green fruits germinating faster than seeds collected from yellow fruits. The density of genninable seeds in the soil seed bank was determined from 94 samples collected beneath the canopy of 24 randomly selected S. mauritianum plants. Of seedlings Ihat germinated, 73% were S. mauritianum and seedling density of S. mauritiallum averaged 16 000 seedlings per hectare. To determine the role of birds in the dispersal of S. mauritianum seeds, observations were made of all birds visiting eleven fruit-bearing plants. To examine the bird's excrement, birds were captured in mist-nets, their excrement collected and any seeds present identified. A total of 340 seeds from 15 plant species were obtained. Four tropical rainforest birds (Australian king parrots (
- Description: C1
- Description: 2003000548
Effects of windthrow on a Eucalyptus delegatensis (Myrtaceae) stand and early understorey succession at Snowy River National Park, Victoria
- Authors: Florentine, Singarayer , Westbrooke, Martin
- Date: 2004
- Type: Text , Journal article
- Relation: Australian Forestry Vol. 67, no. 1 (2004), p. 54-58
- Full Text: false
- Reviewed:
- Description: During June 1998 a very strong windstorm at the Snowy River National Park ncar Mt Gelantipy caused severe damage to a stand of Eucalyptus delegatensis. Little is known about the impact of windthrow on E. delegatensis and subsequent seedling recruitment. This study was undertaken 4.5 y later 10 examine (i) windthrow damage to E. delegatensis and the understorey Acacia dealbata, (ii) the influence of tree size on the pattern of lree damage, (iii) the undergrowth in the windthrow area compared with that in control plots, and (iv) species composition of the soil-stored seed-bank in windthrow and control plots. We found that high winds toppled virtually all trees regardless of size and species, damaging 99% of the E. delegarensis. In windthrow plots there were 49 seedlings ha- I of E. delegarensis and 2210 ha-I of A. dealbata. No E. delegarensis or A. deafbara seedlings were recorded in the control plots. In the soil seed-bank study five species were recovered from soil samples collected from the control, and six from the windthrow-damaged sites. The canopy species E. delegatensis recruited only from the windthrow site. The exotic Rubus fruticosus was found to be colonising the windthrow site, but was not present in the control site. Results show that E. defegarensis recruitment is very poor in the damaged area, and species colonising within that area are light demanding or early succession species. It is proposed that seedling recruitment in the windthrow sites be accelerated by burning the site and broadcasting E. delega/ensis seed, or transplanting seedlings.
- Description: C1
- Description: 2003000710
Evaluation of alternative approaches to rainforest restoration on abandoned pasturelands in tropical north Queensland, Australia
- Authors: Florentine, Singarayer , Westbrooke, Martin
- Date: 2004
- Type: Text , Journal article
- Relation: Land Degradation & Development Vol. 15, no. 1 (Jan-Feb 2004), p. 1-13
- Full Text:
- Reviewed:
- Description: The lag time for natural recruitment of tropical rainforest species in abandoned pastureland is very long, therefore artificial restoration techniques have been employed to accelerate natural seedling recruitment. The objectives of this study were to investigate: (1) the success/failure of establishment 502 seedlings belonging to 15 species from 11 families planted approximately ten years ago; and (2) the influence of different restoration techniques on enhancing natural recruitment during this period. The study was conducted in the wet tropical rainforest region of northeast Queensland, Australia as a completely randomized block design involving five treatments with two replicates. In each plot, 63 tropical rainforest seedlings from one or a combination of species were planted randomly. Two control plots were laid out where no seedlings were planted. Survival, height and diameter data were taken on the seedlings ten years after planting. Each 11×17 m2 plot was further divided into 187, 1×1 m2 subplots. Within each subplot all seedlings recruited were located and identified. Canopy cover was estimated using belt transects 1 m apart that ran in an east-west direction across the plots. Within each plot the percentage of grass, and the crown cover were estimated using the Braun-Blanquet cover abundance scale. Survival rate of planted seedlings varied across the treatment plots. The survival rate ranged from 65 to 75 per cent for primary-promoter species, 85 to 100 per cent in middle-phase species and 42 to 57 per cent for mature-phase species. No Pilidiostigma tropicum seedlings survived in any treatment. Fourteen species recruited naturally across the treatment plots. A total of 410 seedlings were naturally recruited from 11 different families in the ten-year-old reforested site. The highest natural recruitment (236 seedlings) occurred in Treatment 3, where Omalanthus novo-guineensis seedlings were planted with eight primary-promoter species, followed by 99 in Treatment 5 where a group of primary-promoters, middle phase species and mature-phase species were planted together, 36 in Treatment 4 (Alphitonia petriei planted with eight primary-promoter species), 10 in Treatment 2 where only Omalanthus novo-guineensis seedlings were planted, and 13 in control plots. Grass cover declined with increasing species diversity and increased canopy cover. The results indicate that the diversity of species used in restoration had a major influence on natural recruitment. Copyright © 2004 John Wiley & Sons, Ltd.
- Description: C1
- Description: 2003000714
Observations on survival and early growth of natural regeneration in floodplain coolibah Eucalyptus victrix (Myrtaceae) in the Pilbara, Western Australia
- Authors: Fox, John , Florentine, Singarayer , Westbrooke, Martin , Hurst, Cameron
- Date: 2004
- Type: Text , Journal article
- Relation: Rangeland Journal Vol. 26, no. 2 (2004), p. 150-160
- Full Text: false
- Reviewed:
- Description: Observations are presented on the natural regeneration of Eucalyptus victrix L. Johnson and K. Hill (coolibah), the dominant tree species of grassy woodlands on the floodplain of the Fortescue River, north of Newman in the Pilbara district of Western Australia. The main objectives of this study were to examine: (i) survival of newly recruited E. victrix seedlings on flooded and burnt sites, and (ii) growth and survival of established plants in a gilgaied landscape. Populations of newly-recruited seedlings following flooding or fire were monitored opportunistically at 'Marillana' and 'Ethel Creek' stations, for up to two years from tagging. A population of saplings at 'Roy Hill' station was observed over eight years. Seedling densities of E. victrix in flooded sites were 0.32 and 1.03 plants/m2 in 1995 and 1997 respectively. Locally high densities reached from 1.2 to 17.7 plants/m2 on areas of 28 and 6 m2 respectively. At the burnt site at 'Ethel Creek', 1.30 plants/m2 were observed where 58 seedlings were recorded on an area of 445 m2 a year after a natural fire. Many of these persisted well into their second year, whereas seedlings recruited in the flooded sites generally lasted less than a year (250-376 days). In contrast, persistence of a cohort of 100 established saplings <2 m tall in a gilgaied landscape at 'Roy Hill' was high. During 8 years of observations, only one sapling was lost. Those found at the edges of gilgais had attained greater heights (3.91 ± 1.14 m) than saplings located inside (3.16 ± 0.95 m) or on top (3.12 ± 0.93 m) of the gilgais. This study demonstrates that the seedling stage in E. victrix is critical, in that once newly recruited individuals reach the sapling stage (0.6-1 m), mortality rates are much reduced. Unfortunately, it was not possible during the course of this study to locate a cohort of young seedlings that did survive and so any consideration of the conditions necessary for their survival is speculative.
- Description: C1
- Description: 2003000725
Restoration on abandoned tropical pasturelands - Do we know enough?
- Authors: Florentine, Singarayer , Westbrooke, Martin
- Date: 2004
- Type: Text , Journal article
- Relation: Journal for Nature Conservation Vol. 12, no. (2004), p. 85-94
- Full Text:
- Reviewed:
- Description: Tropical rainforests have been disappearing at an alarming rate. In addition to preserving remaining tropical rainforests, we need to convert degraded and abandoned pasturelands into secondary forests. To accelerate this, human intervention in the recovery process is essential. In this review paper we (i) encapsulate some of the problems, which might surface when converting abandoned land to secondary forest. (ii) Look at some of the restoration techniques used in restoration programs and propose additional techniques for consideration. Major barriers to natural regeneration on abandoned and degraded pasturelands are: weed infestation, lack of indigenous soil seed bank, lack of seed supply/movement, soil compaction, depletion of soil nutrients and unsuitable microclimate and microhabitat. Although several restoration techniques have been recommended, most restoration programs have been carried out using native seedling transplants to accelerate natural recruitment. Most restoration groups in the tropics are still in the initial stages of determining which species or species combination to chose to gain maximum benefit. On the other hand restoration ecologists are struggling to detect which techniques are most appropriate to restore degraded and abandoned pasturelands. Our review shows that there is immediate need for further research and development on restoration techniques by examining the ecological and economic effectiveness of: direct seeding, stem cuttings using native pioneer or climax species and simple manipulation such as displacing branches of pioneer species with mature seeds on abandoned and degraded pasturelands and artificial perching to accelerate natural regeneration. These techniques are essential to successfully heal the wound humans have inflicted on the most spectacular and species-rich ecosystems on earth.
- Description: C1
- Description: 2003000720
The germinable soil seedbank of Eucalyptus victrix grassy woodlands at Roy Hill Station, Pilbara District, Western Australia
- Authors: Graham, R.A. , Florentine, Singarayer , Fox, John , Luong, T. M.
- Date: 2004
- Type: Text , Journal article
- Relation: Rangeland Journal Vol. 26, no. 1 (2004), p. 17-33
- Full Text: false
- Reviewed:
- Description: The paper reports soil seedbank species composition, of Eucalyptus victrix grassy woodlands, of the upper Fortescue River in the Pilbara District, Western Australia. In this study, our objectives were to investigate germinable soil seedbanks and species composition in response to three simulated seasons, using emergence. Variation in seed density from three depths was tested. Four field sites were sampled. Thirty samples were collected in late spring, after seed rain and prior to summer rainfall. From each sample spot, three soil depths (surface, 1-5, and 6-10 cm) were segregated from beneath surface areas of 100 cm(2). Samples were later incubated in a glasshouse to simulate three different seasonal conditions (autumn, winter and spring). Germinating seedlings were recorded on emergence and grown until identified. Forty-one species germinated, comprising 11 grasses (7 annuals and 4 perennials), 25 annual herbs and 5 perennial herbs. Distribution patterns of germinable seed in both the important annual grass Eragrostis japonica and the perennial Eragrostis setifolia (a preferred cattle fodder species), suggest that seedbank accumulation differs among species and between sites. In part, this may be associated with the absence of grazing. Species with most total germinable seed were E. japonica (Poaceae; 603/m(2)), and the annual herbs Calotis multicaulis (Asteraceae; 346/m(2)), and Mimulus gracilis (Scrophulariaceae; 168/m(2)). Perennial grass seed was sparse. Spring simulation gave most germination (1059), followed by autumn (892) and winter (376) sets. Greatest species diversity was produced from the spring simulation (33 species), followed by autumn (26), and winter (22). Of the total germination, 92% came from 17 species that were represented in all three simulations. Of the 1227 grass seedlings counted, most were recruited from the surface soil (735), followed by the 5 (310) and 10 (182) cm depths. Marginally more grass seedlings germinated from the spring simulation (558) than the autumn set (523). Only 11.9% of grass germinants came from the winter simulation. All grass species recruited from the soil seedbanks had a C-4 photosynthetic pathway. Except for Cenchrus ciliaris all grass species are native to Australia. Of the four sites sampled, one fenced to exclude cattle five years earlier had significantly more germination than the three unfenced sites. Seedbank sampling produced several new records for plants in the areas sampled.
- Description: C1
- Description: 2003000711
The impact of deforestation and pasture abandonment on soil properties in the wet tropics of Australia
- Authors: Rasiah, Velu , Florentine, Singarayer , Williams, B. L. , Westbrooke, Martin
- Date: 2004
- Type: Text , Journal article
- Relation: Geoderma Vol. 120, no. 1-2 (2004), p. 35-45
- Full Text:
- Reviewed:
- Description: Limited information exists on the changes in soil properties, particularly from the wet tropics of Australia, under long-term abandoned pasture, which was previously grazed and was established on deforested tropical rainforest. This information may be help in successful forest reestablishment. The objectives of this study were to assess the cumulative impact deforestation, grazed and abandoned pasture on selected soil physico-chemical properties from (i) an abandoned pastureland and (ii) a recently planted rainforest (PRF), planted in the abandoned pastureland. The experimental site is a field in the Northeast Queensland (NEQ) wet tropical region of Australia. This site was deforested approximately 70 years ago and brought under unfertilized grazed pasture for 30 years. Subsequently the grazed pastureland was abandoned and remains un-grazed for 40 years. A section of the abandoned pastureland was planted, 10 years ago, with native forest species, involving different combinations in five treatments in a completely randomised block design. A nearby undisturbed rainforest is used as the background against which assessment was carried out. Soil samples from 0- to 15-cm depth were collected in July 2000 and analyzed for nitrate-N, ammonium-N, total N, total soil organic C (SOC) and labile-C, pH (in water and CaCl2), electrical conductivity (EC), exchangeable Ca, Mg, Na, K, and Al, and bulk density. Compared to the rainforest, the N and C concentrations of different forms under abandoned pasture and PRF were significantly less, exclusive of the total N under abandoned pasture. More specifically, the SOC under the abandoned pasture was 37,600 mg/kg compared with 74,800 mg/kg under rainforest and 27,000 mg/kg in the PRF. The exchangeable Al under rainforest was 8.5 c molc/kg compared with 42. 4 to 80.2 c molc/kg under abandoned pasture and PRF. In general exchangeable cations (sum of Ca, Mg, K, and Na) under the rainforest were higher than the abandoned pasture. Soil under the abandoned pasture and PRF are more acidic by 0.5 to 1 units than the rainforest. Higher bulk densities under abandoned pasture and PRF led to 0.03% to 0.07% reductions in total porosities. Though we did not anticipate the soil under the abandoned pasture to recover 100% in 30-40 years, the results indicate that 40 years under abandoned pasture or 30 years of abandoned pasture plus 10 years under PRF was not sufficient to bring about substantial improvement in soil properties comparable to the rainforest. This implies the resiliency of tropical soils, in general, to recover from deforestation and cultivation induced degradation is poor. © 2003 Elsevier B.V. All rights reserved.
- Description: C1
- Description: 2003000713
Arid land vegetation dynamics after a rare flooding event : influence of fire and grazing
- Authors: Westbrooke, Martin , Florentine, Singarayer , Milberg, Per
- Date: 2005
- Type: Text , Journal article
- Relation: Journal of Arid Environments Vol. 61, no. 2 (Apr 2005), p. 249-260
- Full Text:
- Reviewed:
- Description: Arid vegetation is subjected to more or less frequent fire, drought, and sporadic flooding events and grazing. Whilst fire, drought and grazing have been the subject of considerable research, little is known of the impact of flooding in arid environments. In this study we examined opportunistically the effects of a flooding event, and its interaction with fire and grazing on moulding arid vegetation in New South Wales, Australia. We assessed vegetation approximately 2 and 5 years after recession of the water in fenced and unfenced plots subjected to different combinations of flooding and fire. Number of species per area dropped from 11.8 to 5.7 per 625 m(2). Vegetation in plots left open to grazing by vertebrates differed from fenced plots, but the amount of variation explained was small compared with flooding and the change over time. The taxa mostly associated with flooding were Eragrostis spp., Pseudognaphalium luteoalbum and the exotic Nicotiana glauca. Major flooding events not only trigger native species' germination and recruitment but may also create an avenue for exotic species to invade. (C) 2004 Elsevier Ltd. All rights reserved.
- Description: C1
- Description: 2003001050
Ecology of the endangered Southern Shepherd's Purse Ballantinia antipoda (Brassicaceae) and the associated moss mat community on Mount Alexander, Victoria
- Authors: Ambrose, Graeme , Florentine, Singarayer , Seidel, Jessica , Wilson, Michael
- Date: 2005
- Type: Text , Journal article
- Relation: Victorian Naturalist Vol. 122, no. (2005), p. 179-188
- Full Text:
- Reviewed:
- Description: Despite its rarity, conservation status and location within the regional park, there is only limited information on the ecology of B. antipoda. The significance of the micorhabitat provided by the associated moss mat community is unclear.
- Description: 2003001088
Effects of gall induction by Epiblema strenuana on gas exchange, nutrients, and energetics in Parthenium hysterophorus
- Authors: Florentine, Singarayer , Raman, Anantanarayanan , Dhileepan, Kunjithapatham
- Date: 2005
- Type: Text , Journal article
- Relation: Biocontrol Vol. 50, no. 5 (Oct 2005), p. 787-801
- Full Text:
- Reviewed:
- Description: Gall induction by arthropods results in a range of morphological and physiological changes in their host plants. We examined changes in gas exchange, nutrients, and energetics related to the presence of stem galls on Parthenium hysterophorus L. (Asteraceae) induced by the moth, Epiblema strenuana Walker (Lepidoptera: Tortricidae). We compared the effects of galls on P. hysterophorus in the rosette (young), pre-flowering (mature), and flowering (old) stages. Gall induction reduced the leaf-water potential, especially in flowering stage plants. In young and mature stage plants, galling reduced photosynthetic rates considerably. Gall induction reduced the transpiration rate mostly in mature plants, and this also diminished stomatal conductance. Energy levels in most galls and in shoot tissue immediately below the galls were significantly higher than the energy levels in stem tissue immediately above the galls, indicating that the gall acts as a mobilizing sink for the moth. Galling had significant effects on concentrations of minerals such as boron, chloride, magnesium, and zinc. In galled plants, reduced leaf-water potential and reduced rates of photosynthesis, transpiration, and stomatal conductance may have altered mineral element levels. These observed effects demonstrate that E. strenuana has the potential to regulate P. hysterophorus.
- Description: C1
- Description: 2003001078
Exotic plant species invasion in south west New South Wales : Influence of a rare flooding event and grazing
- Authors: Florentine, Singarayer , Westbrooke, Martin
- Date: 2005
- Type: Text , Journal article
- Relation: Plant Protection Quarterly Vol. 20, no. 2 (2005), p. 42-45
- Full Text: false
- Reviewed:
- Description: The main objectives of this study were to investigate: (i) the distribution of exotic plant species in flooded and control (unflooded) areas in relation to a 1997 episodic flooding event and (ii) the influence of grazing in flooded and unflooded open and fenced plots on wed colonization.
- Description: 2003001069